1. Field of the Invention.
The invention in general relates to audio tone signaling devices having piezoelectric transducers and which produce a warble sound signal, and more particularly to such a signaling device which is simple and inexpensive to manufacture.
2. Description of the Prior Art.
Audio tone signaling devices are widely used for applications such as to signal the existence of a condition, the end of an operating cycle, the end of a period of time, or a reminder of something. Because humans can become accustomed to and ignore steady, single-frequency sounds, signal devices which warble or alternate between two frequencies have become common, particularly in alarms. With the proliferation of electronic and other systems which employ alarms and other signaling devices, and the systematic and steady miniaturization and decrease in cost of such systems, it has become important that the alarms and other signaling devices used for such systems be both small and inexpensive so that they do not unduly contribute to the overall size and cost of the system.